12 Mr. Bubble's Notice of a Whin Dyke. 



generally received opinion, that Whin Dykes have been formed by the 

 Basalt, in a state of fusion, having been always forced upwards through 

 the fissures, in the stratification from below, and that they extend to an 

 indefinite depth. It might also shew, that it is doubtful whether these 

 Basaltic fissures, which occur in various parts of the Newcastle Coal- 

 Field, run through the strata in uninterrupted and continuous lines. 

 Although this Dyke has only been proved, in Benwell and Montague 

 Main Collieries, on the South side of the main Dyke, I am inclined to 

 think, that it is a continuation of the line of the Coley Hill Dyke, which, 

 after disappearing for a certain distance on the dip, or opposite side of 

 the Main Dyke, near which it has not been traced, resumes its line of 

 direction here, and proceeds nearly in a direct line through Newcastle 

 Town Moor, by Sandyford Stone, Arkley Dean, Byker, and Lawson's 

 Main, into Walker ; through Walker, into South Hebburn, beyond which 

 it has not been traced underground ; but I consider it to make its ap- 

 pearance again at Simonside, at or about one and a half miles South from 

 Jarrow Church, where the Basalt has been wrought out of it, in consi- 

 derable quantities, for repairing the roads. 



I shall now proceed to state the grounds, on which I have come to the 

 conclusion, that this Dyke is a continuation of the Coley Hill Dyke, and 

 that the Walker Dyke is a further continuation of the same. In short, 

 that the Coley Hill Dyke extends from the Coley Hill to Simonside, 

 -where it appears at the surface, in a similar manner to that in which it 

 presents itself at Coley Hill ; the distance between these two points 

 being, upon the line of the Dyke, about ten and a half miles. See the 

 map, Plate HI. 



Fi-om the Coley Hill we do not discover any appearance of the Dyke 

 at the surface, until we come to the Ouseburn ; here, in the Freestone 

 Quarry, on the East side of the Burn, the Stone, as well as the Clay and 

 Earth above it, and also the debris, which covers the face of the bank 

 from top to bottom, shew that the whole mass has been subjected to a 

 high degree of heat ; and several scattered fragments of Basalt, of 

 various shapes and sizes, occur on the South side of the Quarry. From 

 this point to Simonside, the Dyke never discovers itself at the surface. 



